The incident comes as two US media trade unions called on the Bush administration for an independent inquiry into "record number of deaths" of journalists covering the Iraq war.
The man was wounded in an incident Tuesday in which US soldiers killed an insurgent armed with an AK-47 inciting a crowd at the site of a suicide bombing in eastern Mosul.
The individual, who was not identified, was carrying CBS press credentials, the military said.
CBS on Tuesday said the man was an Iraqi freelance reporter and cameraman employed by CBS News.
"He was standing next to an armed insurgent who was killed at the time that he was injured. The individual in question was carrying press credentials from CBS News," the US military statement said.
"Military officials detained this individual and are conducting an investigation into his previous activities as well as his alleged support of anti-Iraqi insurgency activities.
"There is probable cause to believe that (the detainee) poses an imperative threat to coalition forces."
The military did not say what specifically prompted the detention. It said only that an investigation was under way.
CBS refused to identify the man "for safety reasons."
"The cameraman in question was referred to CBS News by our Iraqi fixer in Tikrit, who has had a trusted relationship with CBS News for two years."
CBS said that, at the time the man was detained, "the Pentagon said forces mistook his camera for a weapon and shot him," and he was later treated in hospital.
Inquiry call
The US Newspaper Guild-CWA and the American Federation of Television and Radio Artists wrote to President George W Bush on the second anniversary of an attack by US forces on the Palestine Hotel in Baghdad on April 8, 2003, in which two journalists were killed.
The unions called on the US administration "to heed the requests from journalists around the world for an independent investigation into the record number of deaths among media staff covering the war in Iraq".
The letter to Mr Bush was part of the International Federation of Journalists' and affiliate organisations' worldwide campaign to keep the public's focus on the danger of covering the war in Iraq, they said.
The IFJ is calling for a full and independent investigation by the United States into 14 media deaths in Iraq.
-AFP